load poixy.txt
[M,N]=size(poixy);
distance=zeros(M);

for i=1:M
    for j=1:M
        distance(i,j) = norm(poixy(i,:)-poixy(j,:));
    end
end
dlmwrite('poi distance.txt', distance, 'delimiter', ' ', 'precision', '%1.9f');
